The 5 min standby issue was driving us mad.
I have discovered that if you connect the Soundbar to the Wi-Fi then it does NOT go into standby. 😀
Note that although I have connected the Soundbar to the Wi-Fi I am using HDMI (ARC) as the Audio source.
I have the same issue with hdmi arc shutting soundbar down after 5 mins with no sound, I ended up switching to wifi connection after reading this and haven't had a problem since, would be nice if they fixed the hdmi arc as I'd rather use that input since wifi skips from time to time and hdmi arc sounds better to me anyway. Thanks.
Found the solution to this when I solved a problem with HDMI AUTO DETECT
Try this works for me no the Soundbar does not turn off after 5 minutes anymore:
The HDMI Auto Detect feature can be turned off on Samsung 2016/2017 TVs using the remote control by pressing a certain key sequence (either IR or Bluetooth remote works).
1. Make sure TV is updated to latest firmware version
2. Switch TV to TV source – HDMI may not work with BT Smart remotes. TV source works with either remote
3. Using IR Remote: Mute + 7 + 2 + 9 + Exit
4. Using Smart Control: Mute + Vol Down + Ch Down + Mute
PLEASE NOTE: TV may or may not display any messages after you press the above key combination. This function is a toggle. So if you want to turn HDMI Auto Detect on again, press the same key sequence.
I am having the same issue...I have spent hours with tech support trying to sort out the issues. I will try the fix posted above on my TV 2017 49QLED but I am skeptical because I still think this is a sound bar issue
Been in contact with Canadian Samsung Customer Support all afternoon about this exact issue. They've escalated it to engineering and I should be in touch with actual Samsung software devs within a couple days.